From practice, a rotary bed is known, in which a reclining frame is arranged on a height adjustable base. The reclining frame is connected to the base by means of a rotary hinge. The reclining frame is essentially separated into three sections: a back section, a central section, and a leg section. The leg section is divided into a proximal and a distal lower section.
With the aid of electromotive drive devices, the reclining frame can be converted from a more or less elongated reclining or bed position into a seat position. For this purpose, the reclining frame is brought 90° from the reclining position into a position perpendicular to the base with the aid of the rotary hinge. The back section of the reclining frame is raised while the distal lower section of the leg section is lowered downward. The central section and also the proximal leg lower section form a sitting surface for the patient.
The distance of the upper edge of the sitting surface to the floor (increased by the thickness of the mattress, if necessary) corresponds to human anatomical proportions. This means that the distance may not be greater than the distance from the back of the knee to the floor, because otherwise the feet of a patient sitting on the bed would not contact the floor. This would thereby make standing up more difficult.
In these known beds, the rotary hinge comprises a circular ring made from an L shaped angle profile arranged on the head of the base. Underneath the circular ring runs a bracing cross, which contacts a bearing socket aligned vertically at the interface of the braces. A rotary peg, which is connected to a frame of the rotary hinge, is seated in this bearing socket so that it can rotate. The frame of the rotary hinge comprises spars, which are arranged along the edges of a square, where the edge length corresponds to the diameter of the circular ring. In the middle of the longitudinal spars, rollers are supported, which run on the top side of the circular ring. The spars of the intermediate section of the reclining frame are rigidly connected to the square frame of the rotary hinge by means of posts. When a load is applied to the reclining frame, the rollers take up the compression forces, while the tensile forces are introduced into the base via the axial peg and the socket.
The structural height of the rotary hinge is relatively great, which requires that the base contact the floor directly without any free clearance. The base cannot be further compacted for two different reasons: the braces forming the base have certain minimum cross sections, so that they are able to receive forces without causing deformation when a load is applied to the bed. At any rate, the bed must be dimensioned for a patient weight of approximately. 180 kg. The other initial condition preventing the base from being further compacted is the applied forces on the drive device. The more the base is compacted, the shorter the lever arms on the individual crank levers, with the aid of which the base is elongated by the drive device.
Further increase of the structural height in the known rotary bed construction is produced from the fact that spacing, in which the drive devices for the leg section and the back section are to be accommodated, must be provided between the reclining frame and the frame of the rotary hinge. The required drives are located above the frame of the rotary hinge because its interior is likewise filled with a bracing cross for holding the axial peg.
These issues prevent the base from being set on feet in the known rotary bed; instead the bed must directly contact the floor with the lower spars or braces. However, such an arrangement is unfavorable ergonomically since care personnel must maintain a spacing corresponding to the size of their feet from the reclining frame. At best, the care personnel can place their feet directly on the base, which results in a considerable spacing between the lower leg of the care personnel and the edge of the reclining frame. The care personnel cannot be supported with the lower leg or knee against the edge of the bed when caring for the patient in the bed, so that ergonomically unfavorable proportions are created.